You only need a trout stamp if you are going to keep trout. So, a MO license and you're good to go.
You can catch fish throughout the blue ribbon area.
You're good to go with what you have for flies - yes, maybe some glo bugs. There's a lot of threads you can lookup on flies.
Access spots: Tan Vat, Baptist, Parker and Cedar Grove (where the white ribbon portion starts). There's also a few parking spots near where the park ends and the BR begins, but I suspect those will be filled quick this weekend.
River should be back in decent shape by the weekend.
Have fun!